
import re

a=''
with open("1.txt","r") as f:
    a=f.read()
re1=re.findall(r"{(.+?)}",a)

txt=''
for i in re1:
    txt+=i

from collections import Counter
txt = Counter(txt.lower())
txt = txt.most_common()
flag=""
for i in txt:
    flag+=(i[0])
print(flag)

